• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.79-86
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• 2012

This study was performed to investigate the physiochemical properties and anti-diabetic effect of yacon vinegar by two-step fermentation. Yacon was matured at room temperature for 20 days. The sugar content of yacon juice prepared from mature yacon was approximately $14^{\circ}Brix$. In the first stage, yacon wine was produced from the juice at $28^{\circ}C$ for 6 days. In the second stage, acetic acid fermentation was conducted at $30^{\circ}C$ and 200 rpm for 6 days to produce yacon vinegar with 4.75% acidity. The major free sugars of yacon vinegar were glucose and fructose at 2,072.12 mg% and 463.95 mg%, respectively. The acetic acid content was the highest of the major organic acids at 3,881.44 mg%. The total free amino acid content was 62.88 mg% with the main free amino acids being proline, ${\gamma}$-amino-n-butyric acid and ornithine. The major minerals of yacon vinegar were Ca, K and Mg. The in vivo anti-diabetic activity of yacon vinegar was investigated in high-fat diet (HFD)/streptozotocin (STZ)-induced diabetic mice. Diabetic mice were administered orally with 10% yacon juice and two yacon vinegars (5% and 10%) at a dose of 7 mL/kg body weight once per day for 4 weeks. Five% yacon vinegar improved the fasting blood glucose levels and glucose tolerance test significantly compared to the diabetic control group (p<0.05). Yacon vinegar increased the pancreatic C-peptide concentration in a dose-dependent manner. These results show that 5% yacon vinegar has a more potent effect on ameliorating hyperglycemia than 10% yacon juice.

• Journal of Mushroom
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• v.16 no.1
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• pp.22-30
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• 2018

This study was performed to determine optimal extraction conditions of fermented Polygonum multiflorum root by Lentinula edodes (JMI10079) Pegler mycelials using response surface methodology. The independent factors were extraction temperature (X1: $40-100^{\circ}C$), extraction time (X2: 2-10 hrs.), and the ratio of water to sample (X3: 33-100 mg/mL). Their effects were assessed on dependent variables of the extract properties, which included soluble solid contents (Y1), $^{\circ}Brix$ of sample extract (Y2), total polyphenol content (Y3), total flavonoid content (Y4), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation scavenging activity (Y5) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (Y6). The experimental data obtained were fit to a second-order polynomial equation. The optimal extraction conditions for fermented P. multiflorum root were: X1: $91.22^{\circ}C$, X2: 7.72 hrs, and X3: 39.71 mg/mL.